Apparatus for measuring absorbed power

ABSTRACT

In an apparatus for measuring absorbed power including an electromagnetic field probe  1  fixedly mounted within a head simulation phantom  2  which simulates the configuration and the electromagnetic characteristics of a head of a human body, and wherein the strength of an electric field or a magnetic field of a radio wave externally irradiated upon the head simulation phantom  2  is measured by the electromagnetic field probe  1 , and the power of the radio wave absorbed by the head is estimated on the basis of measured values, the head simulation phantom  2  comprises a solid dielectric  10 ′ which simulates the configuration and the electromagnetic characteristics of a head of a human body or a liquid dielectric  10  which simulates the electromagnetic characteristics of a head of a human body and which is filled in an enclosed vessel  10  which simulates the configuration of a head of a human body. The volume of the solid dielectric  10 ′ or the volume of the enclosed vessel  11  is equal to or less than 5×10 5  mm 3 .

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.10/398,205 filed Apr. 7, 2003, now U.S. Pat. No. 7,186,377, which is theNational Stage of PCT/JP02/08125, filed Aug. 8, 2002, and in turn claimspriority to Japan Patent Applications 2001-240926 filed Aug. 8, 2001 and2002-68521, filed Mar. 13, 2002 the entire contents of each of which arehereby incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to an apparatus which uses a phantomsimulating the electromagnetic characteristics of a human body tomeasure the amount of absorption by the human body of a radio wave orwaves radiated from a radio transmitter which is operated in thevicinity of the body through a relative scan of the phantom and theradio transmitter.

BACKGROUND ART

In the prior art practice, the power absorbed by a human body, forexample, by the head of the human body, has been estimated byconstructing a head simulation phantom which simulates the configurationand the electromagnetic characteristics of the head of the human bodyand measuring the amount of power absorbed by the phantom.

A conventional example of the prior art will be described with referenceto FIG. 1. A head simulation phantom 2 is constructed by forming arecess 12 configured to divide the head of the human body into two equalparts laterally in a top surface of a vessel 11 and filling the recess12 with a liquid medium 10 which simulates the electromagneticcharacteristics of the head. By way of example, the liquid medium for a900 MHz solution comprises 56.5% of sucrose, 40.92% of deionized water,1.48% of sodium chloride, 1.0% of hydroxyl cellulose and 0.1% ofbactericide as disclosed in a literature IEC/PT62209, “Procedure toDetermine the Specific Absorption Rate (SAR) for Hand-held MobileTelephones” or the like. A radio transmitter 3 which represents a radiowave radiation source is secured to the bottom surface of the vessel 11on the outside thereof at a location central of the vessel 11 or whichcorresponds to the ear of the head of the human body. An electromagneticfield probe 1 which detects an electric or a magnetic field is insertedinto the liquid medium 10 and is scanned in a plane which opposes theradio transmitter 3. In this instance, the head simulation phantom 2 andthe radio transmitter 3 are separately secured and only theelectromagnetic field probe 1 is moved as indicated by arrows 8 forpurpose of scan. A resulting detected value of the electromagnetic fieldprobe 1 is squared, and the squared value is multiplied by a calibrationfacter to determine the absorbed power which occurs within the headsimulation phantom 2. Broken lines 6, shown laterally offset, representthe locus of scan of the probe 1, and this corresponds to themeasurement of absorbed power from the radio wave in a situation thatthe mobile telephone is located close to the ear of the head of thehuman body during the transmission and reception with the antenna (notshown) of the radio transmitter 3 extending in a direction through thecasing of the radio transmitter 3 which runs substantially parallel tothe bottom surface of the vessel 11.

The head simulation phantom 2 shown in FIG. 1 is filled with the liquidmedium 10, and is inconvenient in its handling. Since the probe 1 ismoved within the liquid medium 10 for purpose of scan and measurement,the liquid medium 10 remains open to the air, and there arises a problemthat the liquid medium 10 may be evaporated to cause an aging effect ofthe electromagnetic characteristics thereof.

Another example of the prior art will be described with reference toFIG. 2. A head simulation phantom 2 which simulates the configurationand the electromagnetic characteristics of the head of the human body isconstructed, and an electromagnetic field probe 1 is inserted into anopening 21 formed in the phantom 2. The electromagnetic field probe 1 islocated close to the ear of the head simulation phantom 2, while a radiotransmitter 3 which represents a radio wave radiation source ispositioned on the external surface of the head simulation phantom 2close to the ear. The transmitter 3 is moved vertically andback-and-forth, as indicated by arrows 8, for purpose of two-dimensionalscan while deriving a detected value from the electromagnetic probe 1,and multiplying a calibration factor to the square of the detected valueto determine the absorbed power. The locus of scan for this case isillustrated by broken line 6, shown laterally offset. It is assumed inFIG. 2 that a mobile telephone is used as the radio transmitter 3 withan antenna extended from the telephone case to simulate the manner ofuse of a mobile telephone.

The phantom 2 shown in FIG. 2 simulates the head of the human body by aspherical solid dielectric 10′ or by a liquid dielectric (liquid medium)10 which fills the interior of a spherical vessel. The solid dielectric10′ has a dielectric constant ∈r′=52 and a dielectric loss tanδ=55% (at900 Mhz), for example, and comprises 57% of polyvinylidene fluoride, 10%of ceramic powder and 33% (volume %) of graphite powder, as disclosed ina literature by H. Tamura, Y. Ishikawa, T. Kobayashi and T. Nojima “ADry Phantom Material Composed of Ceramic and Graphite Powder,” IEEETrans. Electromagn. Compat., Vol. 39, No. 2, pp 132-137, May 1997 or thelike.

Assuming that the head phantom2 is formed with a size simulating thehead of the human body, or with a sphere having a diameter of 200 mm, itcontains a volume of 4×π×{(200/2)mm} ³/3. The dielectric which simulatesthe electromagnetic characteristics of the head of the human body has adensity which is equal to about 0.002g/mm³ for the solid dielectric 10′and which is equal to about 0.001g/m³ for the liquid dielectric (liquidmedium). Accordingly, the head simulation phantom 2 has a weight whichis equal to the volume 4×π×{(200/2)mm} ^(3/)3 multiplied by the density0.002g/mm³ or 8400 g for the solid dielectric 10′. Since the liquiddielectric 10 has a density which is nearly one-half that of the soliddielectric 10′, the phantom will have a weight which is nearly one-halfthat of the solid dielectric 10′ phantom. Thus, a conventional headsimulation phantom 2 has a weight which is as high as 4200g or 8400g,and presented an inconvenience in its handling and transportation.

The purpose of measuring the absorbed power is to know how much of aradio wave is absorbed by the human body during the use of a mobiletelephone or a transceiver, and the measurement takes place in aso-called near field in which a distance from a radio wave radiationsource to the phantom 2 is normally very small. As a consequence, thereis a great influence that the reproducibility of positional relationshipbetween the radio transmitter 3, the head simulation phantom 2 and theelectromagnetic field probe 1 has upon the reproducibility of results ofmeasurement. In other words, if there is a relatively small shift in therelationship, there occurs a change in the reflection characteristic ofthe phantom 2, producing a change in the distribution of the radiatedelectromagnetic field. If the radio transmitter 3 is held by the hand 4′of a measuring personnel as indicated in FIG. 3, it is difficult tomaintain a correct position of the transmitter relative to the phantom2, and a good reproducibility of measured values cannot be guaranteed.There also occur influences that the radio wave radiated from the radiotransmitter 3 is absorbed by the hand 4′ of the measuring person andthat the current distribution on the antenna 5 of the radio transmitter3 may be changed due to the hand 4′ of the measuring personnel. Wherethe radio transmitter has a bulky volume or heavy, it may be difficultto conduct a spatial scan of the radio transmitter 3 relative to thephantom 2 by hand 4′.

Conversely, if the radio transmitter 3 is fixed while the absorbed powermeasuring assembly 7 comprising the head simulation phantom 2 and theelectromagnetic field probe 1 scans through a two-dimensional movementrelative to the radio transmitter 3, it is a troublesome operation toperform the measurement by manually moving and scanning the absorbedpower measuring assembly 7 when the head simulation phantom 2 has aweight which is as high as 4200g or 8400g as described above.

It is an object of the present invention to provide an apparatus formeasuring absorbed power which permits a scan through a relativemovement between an absorbed power measuring assembly comprising asimulation phantom and an electromagnetic field probe and a radiotransmitter to be performed in a relatively simple manner.

DISCLOSURE OF THE INVENTION

According to one aspect of the present invention, in an apparatus formeasuring absorbed power in which an electromagnetic field probe isinserted inside a phantom which simulates the configuration and theelectromagnetic characteristics of part of a human body, and the fieldstrength of an electric field or a magnetic field of a radio wave whichis externally irradiated upon the simulation phantom is measured, andthe power of the radio wave which is absorbed by the part of the humanbody is estimated on the basis of measured values, the simulationphantom has a volume which is equal to 5×10⁵ mm³ or less.

More preferably, at least part of the simulation phantom which isdisposed opposite to the radio transmitter is coated by a spacercomprising a material of a lower dielectric constant than the phantom.

According to another aspect of the present invention, in an apparatusfor measuring absorbed power in which an electromagnetic field probe isinserted inside a phantom which simulates the electromagneticcharacteristics of a human body, the field strength of an electric fieldor a magnetic field of a radio wave which is externally irradiated uponthe phantom is measured by the electromagnetic field probe, and thepower of the radio wave which is absorbed by the human body is estimatedon the basis of measured values, there is provided a scan mechanismwhich performs a relative movement between the phantom and the radiotransmitter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a conventional apparatus for measuringabsorbed power using a head simulation phantom in which a liquiddielectric (liquid medium) is used;

FIG. 2 is a perspective view of a conventional apparatus for measuringabsorbed power in which an electromagnetic probe is inserted inside ahead simulation phantom and an absorbed power measuring assembly isfixed while spatially scanning a radio transmitter.

FIG. 3 is a perspective view of a conventional apparatus for measuringabsorbed power in which a radio transmitter is manually held by ameasuring personnel for purpose of scan;

FIG. 4 illustrates a power absorption by a head simulation phantom;

FIG. 5 shows a layout of a calculation model including a head simulationphantom and a half-wavelength dipole antenna acting as a radio waveradiating source in order to calculate a distribution of theelectromagnetic field within the phantom;

FIG. 6 graphically shows a normalized power calculation value at thelocation of the electromagnetic field probe which is to be disposedinside the head simulation phantom, plotted against an antenna positionas measured along the length of the antenna;

FIG. 7A is a cross section showing an example of an absorbed powermeasuring assembly with the apparatus according to the invention whichuses a solid dielectric 10′;

FIG. 7B is a cross section showing an example of an absorbed powermeasuring assembly in the apparatus of the invention which uses a liquidmedium 10;

FIG. 8 is a perspective view illustrating the set-up in which a radiotransmitter is fixed while an absorbed power measuring assemblyaccording to the invention performs a spatial scan;

FIG. 9 is a cross section showing an example in which a spacer isapplied to part of a phantom;

FIG. 10 is a cross section showing an example in which the entiresurface of the phantom is covered by a spacer;

FIG. 11 illustrates that the portion of the phantom which is covered bythe spacer is maintained in contact with the radio transmitter while itis subject to a moving scan, permitting a constant distance to bemaintained between the phantom and the radio transmitter;

FIG. 12 illustrates the use of detachable spacers having differentthicknesses in order to change the distance between the head simulationphantom and the radio transmitter, FIG. 12A being a cross section for asmall spacing, FIG. 12B a cross section for an intermediate spacing andFIG. 12C a cross section for a greater spacing.

FIG. 13 is a perspective view of part of an exemplary spacer having avariable thickness;

FIG. 14 illustrates the use of the spacer shown in FIG. 13, allowing thedistance between the head simulation phantom and the radio transmitterto be changed;

FIG. 15A shows another example of a phantom with a handle gripped by ameasuring personnel;

FIG. 15B shows a further example of a phantom with a handle which isgripped by a measuring personnel;

FIG. 16A shows a simulation phantom formed by an ellipsoid;

FIG. 16B shows a simulation phantom formed by a regular cube;

FIG. 16C shows a simulation phantom formed by a rectangular body;

FIG. 16D shows a simulation phantom formed by a solid cylinder;

FIG. 17A is a perspective view of a head simulation phantom whichrelatively closely simulates the configuration of a head and having ameasuring plane which corresponds to the front of a face;

FIG. 17B is a perspective view of a head simulation phantom whichrelatively closely simulates the configuration of a head and having ameasuring plane which corresponds to the side of a face;

FIG. 18A is a perspective view of an embodiment of the second invention;

FIG. 18B is a perspective view showing an exemplary engagement retainingmechanism for maintaining a slidable relationship between a drive barand a retainer with the bottom surface of a retainer 4 shown in FIG. 18Adisposed upside;

FIG. 19 illustrates an example of a range of measurement obtained whenthe absorbed power measuring assembly 7 undergoes a two-dimensional scanin the arrangement of FIG. 18A;

FIG. 20 is a cross section showing an example of an absorbed powermeasuring assembly 7 which uses a liquid medium 10;

FIG. 21 is a perspective view of an exemplary absorbed power measuringassembly in which a plurality of electromagnetic field probes arefixedly mounted as a linear array within the phantom;

FIG. 22 is a perspective view of another absorbed power measuringassembly in which a plurality of electromagnetic field probes arefixedly mounted as a matrix inside the phantom;

FIG. 23 is a perspective view illustrating the situation that theradiation of a radio wave from a radio transmitter is influenced, notonly by the phantom, but also by aerial condition during the scan;

FIG. 24 is a perspective view of an example of a phantom in the form ofa flat plate which can be regarded as having an infinity size as far asa radio transmitter is concerned;

FIG. 25 is a perspective view of an example of a scan mechanism whichcomprises a belt conveyor;

FIG. 26 is a perspective view of an example of a plurality ofelectromagnetic field probes disposed within the phantom and which aredisposed perpendicular to the direction of movement of the beltconveyor;

FIG. 27 is a perspective view of another example in which a plurality ofelectromagnetic field probes disposed within the phantom are disposed atan angle with respect to the direction of movement of the belt conveyor;

FIG. 28 is a perspective view of an example of an absorbed powermeasuring assembly comprising a plurality of phantoms which are formedto an equal configuration from an equal material and a plurality ofelectromagnetic field probes which are secured at different positionswithin the respective phantoms;

FIG. 29 is a perspective view of an example of an absorbed powermeasuring assembly comprising a plurality of phantoms formed to the sameconfiguration and from the same material and a plurality ofelectromagnetic field probes which are secured at an identical positionwithin the respective phantoms;

FIG. 30 is a perspective view of an example illustrating a positiondetecting sensor which is mounted on the phantom;

FIG. 31 is a perspective view of an example in which a plurality ofposition detecting sensors are mounted on the phantom in a manner tosurround the electromagnetic field probe;

FIG. 32 is a perspective view of a radio anechoic box in which anabsorbed power measuring assembly and a scan mechanism are entirelyconfined;

FIG. 33 is a perspective view of an example of a radio anechoic box inwhich an absorbed power measuring assembly is confined and through whicha belt conveyor passes; and

FIG. 34 is a perspective view of a modification of FIG. 33.

BEST MODES OF CARRYING OUT THE INVENTION

First Invention

The principle of one aspect of the present invention will be describedfirst. When the head simulation phantom 2 which simulates theconfiguration and the electromagnetic characteristics of the head of thehuman body shown in FIG. 2 is irradiated with a radio wave in SHF band,which represents a transmission frequency of a mobile telephone, or witha radio wave of a higher frequency band, the absorption of the power bythe phantom 2 takes place in a manner indicated in FIG. 4. As shown, theabsorption will be greater in a surface layer 2 a of the head simulationphantom 2 which is located close to the radio transmitter 3, but will bereduced in the inner thin layer 2 b, and will be substantially equal tozero in the inside 2 c. Specifically, when a half-wavelength dipoleantenna is disposed at a distance of 10 mm with respect to the phantom 2having a diameter of 200 mm, for example, and a radio wave (of frequency900 MHz) is irradiated upon the phantom 2, it follows that denoting theabsorption of the power of the radio wave which occurs at the surface ofthe phantom 2 by 1, the absorption at a point which is removed 20 mmfrom the surface of the phantom will be reduced to 1/10, and will bereduced to 1/100 when removed 50 mm. In this manner, most part of thephantom is not concerned with the measurement of absorbed power exceptfor a very small portion which is located very close to the surface ofthe head simulation phantom 2. According to one aspect of the presentinvention, an advantage is taken of this by reducing the volume and theweight of the head simulation phantom 2. If there is a significantamount of absorption of the radio wave at a location disposed deepinside the phantom 2, a reduction in the volume of the phantom 2 willresult in removing an internal portion where the absorption of the radiowave is occurring to prevent the measurement from the inner portion.However, such likelihood is eliminated since the absorption of the radiowave occurs only a portion thereof which is located close to thesurface. It is to be noted that eyes and nose displayed in phantom linesin FIG. 4 merely indicate that this phantom simulates the head.

The fact that there is no problem when the volume of the phantom 2 isreduced will be discussed below.

A model is considered as illustrated in FIG. 5. A sphere having adiameter of Dmm, a dielectric constant ∈r′=51.8 and a conductivityσ=1.43S/m is used as a head simulation phantom 2. The phantom 2 isformed with a probe insertion opening 21 which extends from a point onthe surface through the center to a point close to the opposite surface.The probe insertion opening 21 has a diameter of 10 mm, and it isassumed that a distance from the inner end of the opening to the surfaceof the head simulation phantom 2 is equal to 10 mm. A half-wavelengthdipole antenna 5 is vertically disposed at a location which is spaced by10 mm from the surface of the head simulation phantom 2 which opposesthe inner end of the probe insertion opening 21. FIG. 6 graphicallyshows a result of calculation for a normalized power Pn (as referencedto the power which prevails for L=0), plotted against the height Lmmwhen the half-wavelength dipole antenna 5 is moved vertically up anddown from a reference point where the feed point is located opposite tothe inner end 21 a. The normalized power at the location where theelectromagnetic field probe 1 is disposed or at the inner end 21 a ofthe probe insertion opening 21 can be calculated according to thefinite-difference time-domain method (see, for example, “FiniteDifference Time Domain Method for Electromagnetics,” Karl S. Kung andRaymond J. Luebbers, CRC Press 1993 or the like). It is to be noted thatthe input power to the half-wavelength dipole antenna 5 is maintainedconstant, and the frequency of the radiated wave is 900 MHz. A curvewhich links ∘ plots corresponds to a diameter D of the phantom 2 whichis equal to 200 mm (conventional one), a curve which links □ plotscorresponds to a diameter D equal to 100 mm, and a curve which links ⋄plots corresponds to D equal to 40 mm.

It will be seen that the normalized power distribution for D=100 mm issubstantially similar to the normalized power distribution of theconventional phantom in which D=200 mm. Thus, it is considered that ifthe diameter of the head simulation phantom 2 is reduced to one-half theconventional value, or if the volume and the weight are reduced to ⅛times the conventional value, it is still possible to simulate the headof a human body. When the head simulation phantom 2 having D=100 mm ismanufactured, the volume will be 4×π×{(100/2) mm}^(3/)3=5×10⁵ mm³, andits weight will be 4×π×{(100/2) mm}^(3/)3=5×10⁵ mm³ multiplied by0.002g/mm³ or 1000 g when the solid dielectric 10′ is used, and theweight will be further reduced to one-half when the liquid medium 10 isused. The weight of the head simulation phantom 2 which is on the orderof 500g or 1000 g means that a measuring personnel can easily handle thephantom 2 and move it for purpose of scan. When the diameter D isreduced to one-fifth or D=40 mm, the normalized power which issubstantially equal to the conventional one having D=200 mm can beobtained if L is located within 20 mm. However, when the value of Lincreases to the order of 60 mm, the normalized power will be nearlytwice the normalized power obtained with the conventional one havingD=200 mm. The tendency that the normalized power increases above thevalue obtained with a conventional one having D=200 as the distancebetween the probe 1 and the antenna feed point increases occurs for adiameter D which is equal to or less than 100 mm. However, if therequired range of measurement L is small, there is no problem. When therange of measurement L increases, it is possible to reduce the weightand the cost required even though the accuracy of measurement isdegraded. It is to be noted that with a phantom having a diameter Dwhich is equal to or greater than 100 mm, there is a less contributionto reducing the weight and the cost required even though a higheraccuracy can be obtained.

Consequently, in an embodiment of the present invention, a phantom 2which simulates the configuration and the radio wave absorptioncharacteristics of part of the human body or the head in the example tobe described below comprises a phantom 2 as shown in FIG. 7A in which asphere is formed with the solid dielectric 10′ comprising the materialsmentioned above in connection with FIG. 2, for example. In particular,the volume of the phantom 2 is chosen to be equal to or less than ⅛times the volume of part of the human body being simulated, or thevolume of the normal head of the human body or 5×10⁵ mm³. The less thevolume of the phantom 2, the better in respect of reducing the weight,even though the accuracy of measurement becomes degraded as mentionedabove. Accordingly, a minimum value for the volume of the phantom 2 maybe chosen to be a volume which permits at least the probe 1 to becontained even though the accuracy of measurement may be degraded to adegree. A probe insertion opening 21 is formed extending from a point onthe surface of the phantom 2 and extending to another point locatedclose to the surface, and an electromagnetic field probe 1 is insertedinto the probe insertion opening 21. For example, an adhesive 14 isfilled into the probe insertion opening 21, thus securing theelectromagnetic field probe 1 within the phantom 2 to be integraltherewith.

It will be seen from the above description with reference to FIG. 4 thata spacing D1 between the electromagnetic field probe 1 and the closestsurface of the phantom 2 be preferably within 20 mm, in particular,within 10 mm in order to achieve a certain accuracy of measurement.While it is preferred to have a smaller value for D1, a suitable valueis chosen in consideration of the ease of manufacture and a resistanceto fracturing. As indicated by single dot chain lines in this Figure, alead wire 1 a of the probe 1 is connected to a calculation and displayunit 80 in the similar manner as a conventional apparatus of this kind,and the calculation and display unit 80 calculates and displays theabsorbed power using the values detected by the probe 1 and using theabsorption effect.

As shown in FIG. 7B, a head simulation phantom 2 may be constructedusing a confined vessel 11 which simulates the configuration of the headand a liquid medium 10 which fills the vessel 11. The liquid medium 10may be similar to that mentioned previously in connection with FIG. 1.In this instance, the volume of the phantom 2 is again chosen to beequal to or less than ⅛ times the volume of the normal head of the humanbody or 5×10⁵ mm³. The confined vessel 11 is formed with a probeinsertion opening 21 in the similar manner as in FIG. 7, into which anelectromagnetic field probe 1 is inserted and may be secured by using anadhesive 14, for example, to be integral with the phantom 2. The vessel11 is formed of a material such as acrylic resin or Teflon (registeredtrademark) having a low dielectric constant which is close to that ofthe air pereferably, thus preventing the distribution of a radio waveradiated from a radio transmitter 3 (not shown) from being disturbed. InFIGS. 7A and 7B, in order to connect the electromagnetic field probe 1to be integral with the phantom 2, other techniques than filling theadhesive 14 into the probe insertion opening 21 may be used to securethem together.

The spherical head simulation phantom 2 shown in FIGS. 7A and 7B has itsvolume reduced to or less than 5×10⁵ mm³ which corresponds to ⅛ timesthe volume of the conventional phantom which represents the size of thehead of the human body, and the weight is reduced to or less than ⅛times the weight of the conventional phantom, and thus is greatlyreduced in weight. The weight will be equal to or less than 500 g whenthe liquid medium 10 is used, and will be equal to or less than 1000 gwhen the solid dielectric 10′ is used. Accordingly, while the radiotransmitter 3 is retained by and fixed on a retainer 4 as illustrated inFIG. 8, a measuring personnel can hold the phantom 2 by one hand andeasily move it in the directions indicated by solid line arrows 8 inproximity to the radio transmitter 3 for purpose of scan. The locus ofscan 6 of the probe 1 is shown offset in this Figure. Alternatively, thephantom 2 may be fixed while the radio transmitter 3 may be moved indirections indicated by broken line arrows 8. The normalized powerdistribution will be substantially similar to the normalized powerdistribution of a conventional arrangement where D=200 mm. The volume ofthe solid dielectric 10′ or the volume of the confined vessel in whichthe liquid medium 10 is filled, which constitutes the head simulationphantom, is reduced, thus reducing the cost of materials and themanufacturing cost by a corresponding amount. In addition, because thephantom 2 is integral with the electromagnetic field probe 1, therelative positional relationship therebetween is easily reproducibleduring the scan movement.

FIG. 9 shows another embodiment of the invention. In this embodiment, atleast a portion of the surface of the head simulation phantom 2 shown inFIG. 7 which is located close to the radio transmitter 3 or the surfaceportion located close to the location of the electromagnetic field probe1 is coated by a thin spacer 22. The spacer 22 may be adhesively securedor detachably mounted using a tacky bonding agent or may be detachablymounted by fitting by choosing its configuration. As shown in FIG. 10,the spacer 22 may coat substantially the entire surface of the headsimulation phantom 2. The spacer 22 is constructed with a material suchas acrylic resin, Teflon (registered trademark), foamed styrol or woodwhich has a low dielectric constant close to that of the air, thusminimizing a disturbance in the distribution of the electromagneticfield which may occur by the presence of the spacer 22.

With this construction, a relative movement can take place eithervertically or back-and forth, as viewed in FIG. 11, between the phantom2 and the radio transmitter 3 for purpose of scan while maintaining thehead simulation phantom 2 and the radio transmitter 3 in contact witheach other, thus maintaining a constant spacing therebetween andimproving the reproducibility of the measurement of absorbed power. Ifthe radio transmitter 3 is formed with a projection, which is appendedthereto, the head simulation phantom 2 can not be damaged by theprojection during the scan which takes place in contact therewith, thuspreventing any damage of a sensor of the electromagnetic field probe 1from occurring. When the spacer 22 is formed around the entire surfaceof the phantom 2, as shown in FIG. 10, the spacer 22 is effective toprotect the phantom 2 from mechanical damage.

The thickness of the spacer 22 simulates the thickness of the ear of thehuman body or simulates the thickness of a cover applied to the radiotransmitter 3, serving the both simulations. Accordingly, it isdesirable that the spacer 22 has a thickness which is on the order of 20mm at maximum and on the order of 1 mm at minimum, and by changing thethickness of the spacer 22, a variety of simulations can take place. Byway of example, as shown in FIG. 12, a plurality of semi-sphericalspacers 22 having mutually different thicknesses may be provided, andare mounted on the phantom 2 in a detachable manner. FIGS. 12A, 12B and12C illustrate that sequentially thicker spacers 22 are mounted in aninterchangeable manner.

By way of example, as shown in FIG. 13, three spacers 22 a, 22 b and 22c are stacked one above another and are coupled together in a slidablemanner. Such coupling is achieved by removing both lateral edges of thespacer 22 a which are located toward the spacer 22 b along the lengththereof to define a wedge-shaped coupler 24 while the surface of thespacer 22 b which is disposed toward the spacer 22 a is formed with acoupling recess 25 in which the wedge-shaped coupler 24 is received inthe manner of a wedge, thus allowing the spacers 22 a and 22 b to sliderelative to each other along their length while securing them togetherin the direction of the thickness. A similar wedge-shaped coupling takesplace between the spacers 22 b and 22 c to couple them in a slidablemanner in the direction of the length while securing them together inthe direction of the thickness.

As shown in FIG. 14, these spacers 22 a, 22 b and 22 c which are stackedone above another are mounted on the phantom 2 so as to be interposedbetween the phantom 2 and the radio transmitter 3. With thisarrangement, by sliding the spacers, it is possible to interpose onlythe spacer 22 a between the phantom 2 and the radio transmitter 3, tointerpose both spacers 22 a and 22 b as shown in FIG. 14 or to interposethe spacers 22 a, 22 b and 22 c. In this manner, the thickness of thespacer 22 which is interposed between the phantom 2 and the radiotransmitter 3 can be changed. The number of stacked spacer 22 is notlimited to three, but may be suitably increased or decreased, and theindividual thickness of the stacked spacers 22 a, 22 b and 22 c can bechosen to be different from each other.

As shown in FIG. 15A, a handle 23 is secured, for example, adhesively,to the open end of a probe insertion opening 21 in the phantom 2 andextends in the direction opposite from the probe insertion opening 21 tomake the radio wave which is radiated from the radio transmitter 3 to befree from the influence of the hand 4′ as the hand 4′ is moved away fromthe radio transmitter 3 when the hand 4′ of a measuring personnel isbrought close to the handle 23 for purpose of scan and measurement asillustrated in FIG. 8, for example. The handle 23 is formed of amaterial having a low dielectric constant such as acrylic resin,fluorine containing resin, foamed styrol resin or wood. The lead wire 1a of the electromagnetic field probe 1 is passed through an opening 26which is formed inside the handle 23 in communication with the probeinsertion opening 21. In this instance, an adhesive 14 is filled intothe opening 26 to secure the probe 1 to the phantom 2. As shown in FIG.15B, the handle 23 may be mounted on the phantom 2 so as to extend in adirection perpendicular to the direction in which the probe insertionopening 21 extends.

The configuration of the head simulation phantom 2 is not limited to thesphere mentioned above, but may assume a geometrically simpleconfiguration such as an ellipsoid as shown in FIG. 16A, a cube as shownin FIG. 16B, a rectangular body as shown in FIG. 16C or a solid cylinderas shown in FIG. 16D as long as the purpose of simulating the head ofthe human body is served. In any event, it has a volume which is on theorder of ⅛ times the volume of the head of a normal man or less, namely,5×10⁵ mm³. Rather than being limited to a phantom which simulates thehead of the human body, a simulation phantom having a configuration asillustrated in FIGS. 16A to D may be constructed to simulate part of thehuman body such as the arm or trunk. In any event, it has a volume whichis equal to or less than ⅛ times the normal volume of part of the humanbody being simulated.

By constructing the phantom as a sphere or a geometrically simpleconfiguration as illustrated in FIGS. 16A to D, a distribution of theelectromagnetic field within the phantom 2 which is not formed with aprobe insertion opening 21 may be analytically obtained using the radiotransmitter 3 as a dipole antenna, and a calibration factor for theelectromagnetic field probe 1 can be determined on the basis of suchanalytical results.

By constructing a phantom 2 which simulates the configuration of thehead of the human body, or simulating the front face of the head by asquare-shaped plane 2 a as a front surface as shown in FIG. 17A, forminga probe insertion opening 21 so that it extends from the rear side to apoint close to the front surface 2A and inserting an electromagneticfield probe 1 therein, an absorbed power measuring assembly 7 which canbe used with a transceiver as the radio transmitter 3 may beconstructed. Eyes and nose indicated by single dot chain lines mayassume configurations which correspond to actual eyes and nose, or maybe a simple plane with dot indications thereon which represents thefront face for the sake of convenience. Alternatively, as shown in FIG.17B, the square-shaped plane 2 a may be provided as a front surfacewhich simulates the lateral side of the face of the head and anelectromagnetic field probe 1 may be inserted therein to construct anabsorbed power measuring assembly 7 which can be used when utilizing amobile telephone as the radio transmitter 3. The ear indicated by singledot chain lines may be configured so as to correspond to the actual ear,or may be a simple plane with a dot indication representing the lateralside of the face for the sake of convenience. When the configuration isrelatively complex as in such a phantom, a distribution of theelectromagnetic field cannot be analytically obtained to determine acalibration factor for the electromagnetic field probe 1, but thefinite-difference time-domain method may be used to derive adistribution of the electromagnetic field numerically, and a calibrationfactor for the electromagnetic field probe 1 can be determinedtherefrom.

While the above description has principally dealt with phantom 2 of atype in which the liquid medium 10 is confined into the enclosed vessel11 as shown in FIG. 7B may be used as phantoms which are used in theembodiments shown in FIGS. 9 to 17. In this instance, since the liquidmedium 10 is sealed, an aging effect in the electromagneticcharacteristics which may result from the evaporation of components canbe prevented while facilitating the handling.

Second Invention

FIG. 18 shows an embodiment of another aspect of the invention, andparts corresponding to those shown in FIGS. 1 to 17 are designated bylike reference characters as used before.

A phantom 2 which simulates the electromagnetic characteristics of thehuman body is provided. In this instance, there is no need to simulatethe configuration of part of the human body. FIG. 18 represents anarrangement in which the phantom 2 is formed with the solid dielectric10′ in the form of a relatively flat cube. A probe insertion opening 21is formed into one surface of the phantom 2 and extends close to theopposite surface 2 a. An electromagnetic field probe 1 is inserted intoand secured in the inner end of the probe insertion opening 21, thusconstructing an absorbed power measuring assembly 7. Securing theelectromagnetic field probe 1 may take place, for example, by way of theadhesive 14 as illustrated in FIG. 7A.

A radio transmitter 3 is disposed in proximity to the location of theelectromagnetic field probe 1 within the phantom 2, and a scan takesplace by a scan mechanism 100 while the radio transmitter 3 is disposedopposite to the phantom 2. In the example shown in FIG. 18, the radiotransmitter 3 is disposed close to and in parallel relationship with thesurface 2 a of the phantom 2 which is located close to the probe 1 whilean antenna 5 of the radio transmitter 3 such as a mobile telephoneextracts from a casing 3 a. The radio transmitter 3 is mounted so thatthe casing 3 a is held gripped by a retainer 4.

The scan mechanism 100 may comprise drive screws 121, 122 extendingalong a pair of parallel sides of a rectangular frame-shaped base 110,for example, and rotatably mounted by four supports 111. Similarly,drive screws 123, 124 are rotatably mounted by the supports 111 on theother pair of parallel sides. A support bar 131 which extends parallelto the drive screws 121, 122 is formed with threaded holes at itsopposite ends, which are threadably engaged with the drive screws 121,122. Also, a support bar 132 which extends parallel to the drive screws123, 124 is formed with threaded holes at its opposite ends, which arethreadably engaged with the drive screws 123, 124. The support bars 131and 132 are slightly offset from each other in a direction perpendicularto the surface of the phantom 2 which is disposed opposite to the radiotransmitter.

As shown in FIG. 18B, pairs of opposing, inverted L-shaped engagingpeaces 141 a and 141 b, 141 c and 141 d, 142 a and 142 b, and 142 c and142 d are fixedly mounted on the surface 4 a of the retainer 4 which isdisposed opposite from the phantom 2, and the support bar 131 passesbetween the pairs of engaging pieces 141 a and 141 b and 141 c and 141 dso as to be slidable between the ends of these engaging pieces and thesurface 4 a of the retainer 4. In the similar manner, the support bar132 is passed between the pairs of engaging pieces 142 a and 142 b and142 c and 142 d so as to be slidable. However, it is to be noted thatthe support bar 132 has its opposite lateral edges received in groovesformed in the ends of the engaging pieces 142 a-142 d, whereby itsmovement in a direction perpendicular to the surface 4 a of the retaineris restricted.

An arrangement is made such that the drive screws 121, 122 can be drivenfor rotation in forward and reverse directions by a controller 151including a motor for example, and the drive screws 123, 124 can bedriven for rotation in forward and reverse directions by a similarcontroller 152. An absorbed power measuring assembly 7 is mounted on asupport 160 which is secured to the base 110 so that the surface 2 a ofthe phantom 2 is disposed close to and opposite to the radio transmitter3 which is retained by the retainer 4.

Accordingly, when the drive screws 121, 122 rotate, the support bar 131moves along the screws 121, 122 depending on the direction of rotationthereof, whereby the radio transmitter 3 also moves in the samedirection. When the drive screws 123, 124 rotate, the support bar 132moves along the screws 123, 124 depending on the direction of rotationthereof, whereby the radio transmitter 3 also moves in the samedirection. Thus, by controlling the controllers 151, 152, atwo-dimensional scan of the probe 1 relative to the radio transmitter 3can take place, as indicated by a locus 6 which is shown offset in thisFigure. For example, the two-dimensional scan is capable of measuringthe power absorbed from the radio wave over the entire surface 2 a ofthe phantom 2 while the antenna feed point 3 b of the radio transmitter3 is disposed opposite to the probe 1. FIG. 19 illustrates by way ofexample that an area 9, shown hatched, over the surface 2 a of thephantom 2 can be measured relative to the radio transmitter 3. It is tobe noted that what is measured by the electromagnetic field probe 1 isvalues on the locus of scan 6, and values in interstices S betweenadjacent scan lines are interpolated from adjacent measured values. Inorder to reduce the time of measurement, rather than using a continuousmeasurement, the measurement takes place at an interval on the scanline, and values in the interval are interpolated from adjacent measuredvalues. The spacing between the adjacent scan lines may be chosen on theorder of 1 cm, for example. The range of measurement (area) 9 ispreferably a rectangular range which is determined by the longitudinallength (inclusive of the antenna length) and the lateral length of theradio transmitter 3.

The phantom 2 used may comprise an enclosed vessel 11 which isconfigured in the similar manner as shown in FIG. 18A and which isformed with a probe insertion opening 21, into which a liquid medium 10is filled, as shown in FIG. 20.

The scan mechanism 100 allows a two-dimensional scan of the absorbedpower measuring assembly 7 relative to the radio transmitter, andaccordingly, the power absorbed from the radio wave by each part of thehuman body which corresponds to the phantom 2, can be measured with ahigh positional accuracy. In addition, a result which is similar to aresult of measurement according to the measuring technique shown in FIG.1 in which the probe 1 is moved for purpose of scan is obtained and thelikelihood that the response of the liquid medium 10 may be changed dueto the evaporation is avoided with the phantom 2 which uses the liquidmedium 10. The scan mechanism 100 is not limited to the exampledescribed above, but a variety of X·Y drive mechanism may be used.

As shown in FIG. 21, a plurality of electromagnetic field probes 1 arefixedly mounted in a linear array within a phantom 2. A moving scan of aradio transmitter 3 obtains a range of measurement shown in FIG. 19 witha stroke corresponding to a spacing S1 between the electromagnetic fieldprobes 1 in the direction of the array of the electromagnetic fieldprobes 1. In FIG. 21, the probes 1 are arrayed in a direction parallelto the lengthwise direction of the radio transmitter 3, but may bearrayed in a direction perpendicular to the lengthwise direction.

As shown in FIG. 22, a plurality of electromagnetic field probes 1 maybe arrayed in a matrix in a plane which is close to the surface 2 a of aphantom 2. In this instance, a measurement over the range shown in FIG.19 can be obtained by scanning in one direction of the array of theelectromagnetic probes 1 through a stroke corresponding to a spacing S1and scanning in the other direction of the array through a strokecorresponding to a spacing S2. Again, a value or values located betweenmeasuring points are interpolated from adjacent measured values. Inconsideration of these, the number of probes 1 which are disposed withinthe phantom 2 is contemplated to be from 1 to the order of 10, and thespacing between the probes are preferably S1=S2=20 mm or so.

With the arrangement shown in FIG. 21, the scan stroke is shorter thanin the example shown in FIG. 18, and the measurement can be completed ina shorter time interval and a scan mechanism 100 can be constructed in acompact form. With the embodiment shown in FIG. 22, the time interval ofmeasurement can be made shorter and the scan mechanism can beconstructed in a smaller size.

As indicated in FIG. 23, when a radio transmitter 3 is brought to aposition A during a moving scan or when the majority of the radiotransmitter 3 is located opposite to a phantom 2, the radiationcharacteristics of the radio transmitter 3 is strongly influenced by thephantom 2, but at position B or when a significant portion of the radiotransmitter 3 is not disposed opposite to the phantom 2 or misalignedtherewith, the radiation characteristics of the radio transmitter 3 isinfluenced by both the phantom 2 and the air.

In consideration of this, as illustrated in FIG. 24, the configurationof a phantom 2 may be chosen to be in the form of a flat plate having aninfinity size as seen by a radio transmitter 3, with the radiotransmitter 3 disposed opposite to a central portion of one surface ofthe plate-shaped phantom 2. In this manner, the influence of the phantomupon the radiation characteristics of the radio transmitter 3 can bemade substantially uniform at any position of the radio transmitter 3during its moving scan. When part of the human body which is locatedclose to the radio transmitter 3 is more planar and its area is greater,the absorption of the radio wave occurs more strongly. Accordingly, whenan absorbed power measuring apparatus is constructed in the manner shownin FIG. 24, a maximum value evaluation can be made. In order for thephantom 2 to be viewed by the radio transmitter 3 as having an infinitysize, its length L1 as measured in the direction in which an antenna 5extends should be equal to or greater than 0.6λ, its length L2 in adirection perpendicular to the antenna 5 should be equal to or greaterthan 0.5λ, and its thickness L3 should be equal to or greater than 0.3λwhere λ represents the wavelength of a radio wave transmitted from theradio transmitter 3.

The phantom 2 may be one which simulates respective part of an actualhuman body as illustrated in FIGS. 7, 16 and 17 or one which employs angeometrically simple configuration. However, it is not necessary thatthe volume of the phantom 2 be equal to the volume of a correspondingpart of the human body. In any event, the measurement takes place by amoving scan of the absorbed power measuring assembly 7 and the radioline transmitter 3 relative to each other using the scan mechanism 100shown in FIG. 18 or the like, for example.

The use of a belt conveyor in a scan mechanism 100 is illustrated inFIG. 25. A belt conveyor 31 is maintained substantially horizontalacross its width and runs substantially horizontally. A drive mechanismfor the belt conveyor 31 is not shown in the drawing. A phantom 2 asmounted on a support 160 is fixedly mounted over the belt conveyor 31.The surface 2 a of the phantom 2 which is located close to a probe 1 isdisposed opposite to the belt conveyor 31 with a spacing D1 with respectto the top surface of the belt conveyor 31. The radio transmitter 3 isplaced on the belt conveyor 31 so that its lengthwise direction extendsin the crosswise direction of the belt conveyor 31 and the direction ofthickness of a casing 3 a extends perpendicular to the top surface ofthe belt conveyor 31. Substantially the entire length of the radiotransmitter 3 passes under the phantom 2, and the spacing D1 is chosenso that the surface 2 a of the phantom 2 is disposed as close to theradio transmitter 3 as possible.

The radio transmitter 3 is placed on an upstream portion of the beltconveyor 31, and as the radio transmitter 3 passes under the phantom 2,a linear scan takes place between the radio transmitter 3 and anabsorbed power measuring assembly 7, thus enabling a measurement. Withthis arrangement, when radio transmitters 3 are successively placed onthe belt conveyor 31, a measurement of the power absorbed by the phantom2 can be automatically made for a number of radio transmitters 3.

As shown in FIG. 26, when a plurality of electromagnetic field probes 1are disposed within a phantom 2 as an array in a crosswise direction ofthe belt conveyor 31, merely placing a radio transmitter 3 on the beltconveyor 31 allows a range of measurement of absorbed power can beextended to a two-dimensional plane. In addition, as shown in FIG. 27,when a plurality of electromagnetic field probes 1 are disposed as anoblique array with respect to the crosswise direction of the beltconveyor 31, the electromagnetic field probes 1 can be kept far awayfrom each other. This allows a reduction in the equivalent dielectricconstant and the conductivity of the phantom 2 under the influence ofthe probe insertion opening 21 which is used to secure theelectromagnetic field probe 1 to be alleviated. In this instance, aphantom 2 in the form of a flat plate has an infinity size as viewedfrom the radio transmitter 3, thus preventing the radiationcharacteristics of the radio transmitter 3 and the antenna reflectedpower from changing as long as the radio transmitter 3 is disposedopposite to the phantom 2.

As shown in FIG. 28, a plurality of phantoms 2, which may be three innumber, having an identical configuration and formed of an identicalmaterial are fixedly mounted as an array in a direction in which a beltconveyor 31 runs. However, an electromagnetic field probe 1 is fixedlymounted in each phantom 2 at a mutually different position as viewed inthe crosswise direction of the belt conveyor 31. In this instance, thephantom 2 has a size which corresponds to a part of the human body. Forexample, the phantom 2 shown in FIGS. 2, 18A and 20 may be used. In thismanner, measured values from the two-dimensional scan includecontributions of configuration of the part of the human body while theresponse of each phantom 2 is little influenced by the electromagneticfield probes 1. The shift of position of the electromagnetic fieldprobes 1 between different phantoms 2 may be chosen in the runningdirection rather than in the crosswise direction of the belt conveyor,or may be chosen in any other suitable manner.

As shown in FIG. 29, a plurality of phantoms 2, which may be three innumber, for example, having an identical configuration and formed withan identical material may be fixedly mounted as an array in the runningdirection of the belt conveyor 31, and an electromagnetic field probe 1is mounted at the same position, for example, at the center of eachphantom 2. As the belt conveyor 31 runs, each radio transmitter 3 issubject to the measurement of absorbed power by three absorbed powermeasuring assemblies 7 under the same condition. A mean value of aplurality of measured values for each radio transmitter 3 may be chosento define the power absorbed from the radio wave from this radiotransmitter 3, or a maximum value among a plurality of measured valuesfor each radio transmitter 3 may be chosen to define the power absorbedfrom the radio wave from this radio transmitter 3. The process ofdetermining such a mean value or a maximum value takes place in thecalculation and display unit 80 shown in FIG. 7.

In an example shown in FIG. 30, a position sensor 51 is mounted on aphantom 2 in order to improve the accuracy of measuring position. Theposition sensor 51 is mounted on the phantom 2 so that its positionrelative to the probe 1 can be defined, thus detecting whether or notthe position sensor 51 is located opposite to a radio transmitter 3. Theposition sensor 51 detects whether or not it is located opposite to theradio transmitter 3 by radiating an infrared pulse beam in a directionperpendicular to the surface 2 a of the phantom 2, for example, anddetermining a time interval until a reflected infrared pulse is receivedor the strength of the reflected infrared pulse. As a scan mechanismperforms a two-dimensional moving scan of the radio transmitter 3, eachpoint where the radio transmitter 3 has been detected can be plotted,whereby the configuration of the radio transmitter 3 which opposes thephantom 2 is detected. Since the relative position between the probe 1and the position sensor 51 in a plane parallel to the scan plane isfixed and is previously known, the position of each measuring point ofthe probe 1 with respect to the configuration of the detected radiotransmitter 3 can be determined, and when the configuration of the radiotransmitter 3 is determined with a high accuracy, the position of themeasuring point of the probe 1 can be determined with a correspondingaccuracy.

When the belt conveyor 31 shown in FIG. 25 is used as the scanmechanism, running the belt conveyor 31 at a constant speed and placingradio transmitters 3 on the belt conveyor 31 at a given time intervalallows the time to be determined when a particular radio transmitter 3reaches the position of the probe 1, by dividing the distance betweenthe position where the radio transmitter 3 is placed on the beltconveyor 31 and the absorbed power measuring assembly 7 by the runningspeed of the belt conveyor 31. In this instance, if the position sensor51 is also used in the absorbed power measuring assembly 7 as shown inFIG. 30, the measuring position of the probe 1 relative to the radiotransmitter 3 can be correctly determined by detecting the arrival ofthe radio transmitter 3 by the position sensor 51, if the position wherethe radio transmitter 3 is placed on the belt conveyor 31 is misalignedor the time interval to place it is offset.

As shown in FIG. 31, by disposing the position sensors 51 so as tosurround the probe 1, the positional relationship between the radiotransmitter 3 and the probe 1 can be determined with a better accuracy.

FIG. 32 shows an exemplary construction in which an absorbed powermeasuring assembly 7 and a scan mechanism 100 are enclosed in a radioanechoic box 41. With this construction, it is possible to prevent anelectromagnetic field probe 1 from detecting undesired radio waves andto prevent a leakage of the radio wave radiated by a radio transmitter 3to the exterior.

When the scan mechanism is constructed with the belt conveyor 31, a pairof opposing walls of the radio anechoic box 41 are formed with openings41 a, 41 b in opposing relationship so as to pass the belt conveyor 31therethrough, and metal tubes 42 a, 42 b are mounted to connect with theopenings 41 a, 41 b, as shown in FIG. 33. The openings of the tubes 42a, 42 b are chosen so that their cut-off frequency is higher than thefrequency of the radio wave radiated from the radio transmitter 3 withinthe radio anechoic box 41, thus preventing the radio wave from the radiotransmitter 3 from passing through the tubes 42 a, 42 b. Alternatively,cloths 43 a, 43 b woven with metal are attached to the upper edges ofthe openings 41 a, 41 b of the radio anechoic box 41 to hang therefrom,as shown in FIG. 34, thus causing the cloths 43 a, 43 b to be forced outof the way by the radio transmitter 3 as it passes through the openings41 a, 41 b.

A phantom using the liquid medium 10 as well as the solid dielectric 10′may be used also in the embodiments shown in FIGS. 21 to 34. It is alsodesirable according to the second invention that the probe 1 be disposedwithin 20 mm from the surface 2 a of the phantom which faces the radiotransmitter 3.

1. An apparatus for measuring absorbed power comprising: anelectromagnetic field probe disposed within a phantom which simulatesthe electromagnetic characteristics of a human body, and wherein thestrength of an electric field or a magnetic field of a radio waveexternally irradiated upon the phantom is measured by theelectromagnetic field probe, and the power of the radio wave absorbed bythe human body is estimated on the basis of measured values; and a scanmechanism which causes a relative movement between the phantom and aradio transmitter, wherein the scan mechanism comprises a belt conveyor,and the phantom is fixedly mounted in opposing relationship with thebelt conveyor while the radio transmitter acting as a radiation sourceof the irradiating radio wave is placed on a surface of the beltconveyor which faces the phantom.
 2. The apparatus for measuringabsorbed power according to claim 1 in which a plurality ofelectromagnetic field probes are disposed within the phantom.
 3. Theapparatus for measuring absorbed power according to claim 1 in which thephantom is in the form of a flat plate and has a size larger than thesize of the radio transmitter acting as a radiation source of theirradiating radio wave.
 4. The apparatus for measuring absorbed poweraccording to claim 1 in which a plurality of electromagnetic fieldprobes are disposed as an array in the crosswise direction of the beltconveyor.
 5. The apparatus for measuring absorbed power according toclaim 1 in which the phantom is in the form of a flat plate having asize larger than the size of the radio transmitter, and a plurality ofelectromagnetic field probes are disposed as an oblique array relativeto the crosswise direction of the belt conveyor.
 6. The apparatus formeasuring absorbed power according to claim 1 in which a plurality ofidentical phantoms are fixedly mounted as an array in the runningdirection of the belt conveyor, and the electromagnetic field probesdisposed within the respective phantoms assume a different position ineach phantom.
 7. The apparatus for measuring absorbed power according toclaim 1 in which a plurality of identical phantoms are fixedly mountedas an array in the running direction of the belt conveyor, and theelectromagnetic field probes disposed within the respective phantomsassume an identical position.
 8. The apparatus for measuring absorbedpower according to claim 1 in which the phantom has a configurationwhich simulates the configuration of the part of the human body.
 9. Theapparatus for measuring absorbed power according to claim 1, furthercomprising a position sensor mounted on the phantom for detectingwhether or not the position sensor is located opposite to a radiotransmitter acting as a radiation source of the irradiating radio wave.10. The apparatus for measuring absorbed power according to claim 1,further comprising a radio anechoic box having two opposite openings forpassing therethrough the phantom and the belt conveyer.